Automatic clamping device for paper-cutting and other machines



.3 1927' J, F. SCHROETER AUTOMATIC CLAMPING DEVICE FOR PAPER CUTTING AND OTHER MACHINES Filed April 8, 1926 4 Sheets-Sheet l l 4-.. ."J I i I l I l l 7! I 1 40,965 30192Z J.F.SCHROETER AUTOMATIC GLAMPING DEVICE FOR PAPER CUTTING AND OTHER MACHINES Filed April 8. 1926 4 Sheets-Sheet 2 ATTORN EY g J. F. SCHROETER AUTOMATIC CLAMPING DEVICE FOR PAPER CUTTING AND OTHER MACHINES INVENTOR fa/0v f1 jay/90575? B Q Aug. 30, 1927. 1,640,965

J. F. SCHROETER AUTOMATIC CLAMPING DEVICE FOR PAPER CUTTING AND OTHER MACHINES Filed April 8. 192,6 4 Sheets-Sheet 4 |NVE NTOR 32 8/ ATTORNEY Patented Aug. 30, 1927.

JOHN F. SCHROETER, 0F ATLANTA, GEORGIA.

AUTOMATIC CLAMPING DEVICE FOR PAPER-CUT'1ING AND OTHER MACHINES.

Application filed April 8,

The object of this invention is to improve and simplify the structure set forth in my Patent No. 1,547,828 dated July 28, 10:25. This object is accomplished by my invention, one embodiment of which is hereinafter more particularly set forth.

For a more particular description of myinvention, reference is to be had to the accompanying drawings, forming a part hereof, in which Figure 1 is a rear elevation, partially in section, of a paper cutter provided with my improved clamping mechanism.

Figure 2 is a sectional view taken onthe line 22 of Figure 1, looking in the direction of the arrows.

Figure 3 shows a portion of the automatic clamping mechanism, and

Figure 4 is a sectional view taken on the line 4-4 of Figure 3, looking in the direction of the arrows. v

Figure 5 is a sectional view showing a detail of the clamping mechanism.

Figure v6 is a sectional view of a modified form of automatic clamping mechanism.

Figures 7 and 8 are sectional. views taken on the lines 7-7 and 8-8, respectively, of Figure 6, looking in the direction of the arrows.

Throughout the various views of the drawings, similar reference characters designate similar parts.

\Vhere cutters are employed, or similar instruments, it is necessary to clamp the paper, or other material, firmly while it is being operated upon. The thickness of this material will vary within the limits of the apparatus and in many instances it is also necessary to have either an automatic power clamp which will accommodate itself to any thickness within the scope of the machine, and manual clamping which will be under the control of the operator, so that the machine may be used either way. Furthermore, this machine must always be reliable and accurate in its operation as any failure in the machine may be disastrous t0 the operator. the material or the machine. One embodiment of my invention which meets these conditions will now be described.

A machine 1 of the type in question is provided with a table 2 carried by a suitable support 3, as side frames, with parts 4 above the table which carry a clamp 5 and a knife 6, in the conventional manner. This knife 6 may be driven in any suitable 1926. Serial No. 100,542.

way. as by links 7, crank pins 8 and cranks 9 secured to a shaft 10 which may be driven by any suitable source of power, not shown, and all of which is conventional. The knife may be guided by a diagonal link 11 which causes it to make a shear cut.

Of course, the knife mechanism may be varied, as desired, and modifications are not shown, as all such structures are old and well known in the art and form no part of this invention. It may be that a punch may be substituted for the knife in which case there would be no draw out. These, or any other desired devices, maybe used, as will be understood, without further reference or description.

The clamp 5 is actuated by mechanism which will now be described. In the embodiment shown this clamp is secured at each end to racks 12 which mesh with segmental gears 13 which are fixed to a shaft 14, the ends of which are suitably mounted in the frame 3 and this shaft may be either manuall driven, for manual clamping, power riven for automatic clamping, or spring driven for raising when no clamping is desired, all of which will now be described.

Manual clamping.

At a suitable location, the shaft 14 has a chain segment 15 to which is secured a sprocket chain 16, or other suitable device, and this chain runs down to a foot treadle 17 pivoted on a shaft 18, the ends of which are secured in the frame 3 in any desired manner. This foot treadle 17 also carries a counterweight 19 in the conventional manner.

In view of the foregoing it is obvious that when the treadle 17 is depressed at its forward end by a foot of the operator, tension is put on the chain 16 which causes it to turn the chain segment 15 and thereby shift the shaft 14 so that this shaft will drive its segment gears 13 in a manner which will cause the racks 12 to be lowered. \Vhen pressure is released from the treadle 17 the counterweight 19 will cause, or tend to cause, a return to normal. The action of this counterweight is assisted by mechanism which will be described below.

Automatic clamping owclaanz'em.

The shaft 10 carries a spur gear 20 which meshes with a corresponding gear 21 on a stud shaft 22 which is suitably mounted and fixed in the frame 3 of the machine. This gear 21 has a boss 23 about its center and from this extends a crank 24 which is provided with a crank pin 25 which is pivotally connected to the link or pitman 26 which elongates and shortens while functioning, in a manner which will be described below. This link or pitman 26 is pivotally connected at 27 to two arms 28 which extend from a boss or sleeve 29 that runs idle on the shaft 14. This sleeve 29 may be kept in position in any desired manner as b a collar 30 which is fixed to the shaft 14 )y a set screw 31 or any other suitable device. One of the gears 13 is preferably projected along the shaft 14 so as to reach the sleeve 29 and this part is provided with an arm 32 with a projection or laterally extending end 33 which is adapted to rest on an arm 28, as shown in Figures 1 and 5. The purpose of this is to allow the shaft 14 to turn without turning the sleeve 29. \Vhen this occurs, the projection 33 is raised off the arm 28, as appears in Figure 2. At other times, the arm 28 may be raised so as to drive the projection 33 in one direction only so that when this occurs, the shaft 14 will be shifted so as to cause a clamping action, as above set forth. A spring mechanism, described below, tends to normally keep the parts 33 and 28 in contact. The lower end of the arm 28, which is engaged by the projection 33, is provided with a cushion stop member 34 which engages a corresponding cushion stop member 35 which is mounted in a bracket 36 which is supported in any suitable manner from the frame 3. The purpose of this is to-limit the swing of the arms 28 in one direction and when so limited, and also when the projection 33 rests on this arm 28, the movement of the shaft 14 is limited, as is obvious. This means that the upper limit of the movement of the clamp 5 1s determined by the engagement of the stops 34 and 35 and also the engagements of the parts 33 and 28.

The link 26 has the two pivots 25 and 27 which have been described above and this link functions so that the distance between these pivots will vary in a manner which will now be described. The crank or pivot 25 is mounted in a crossing 37, as shown in Figure 2, and secured in any suitable manner to two parallel, spiral rack bars 38 which mesh with a corresponding spiral gear 39 and pass through suitable guides 40 with which they have *a sliding contact. The guides 40 form an integral part of clamping sleeves 41 which are held in proper relation by means of bolts 42 which have springs 43 mounted thereon, the tension of whichmay be varied by tightening or loosening the nuts 44 of these bolts 42. The structure of the interior of the clamps 41 is revealed in Fig ure 3. Here it appears that they are lined with leather 45 which leather engages a cylinder 46 and this cylinder is free to turn inside the clamps and against the leather 45. In the preferred embodiment of my invention this cylinder 46 is made hollow and carries at its top a washer 47 through which passes a bolt 48 which is secured to a plug 49 and the plug 49 and cylinder 46 are keyed so as to make up friction cylinder and hearing for spiral gear 39. From this it is apparent that the plug 49 and cylinder 46 can be kept in fixed relation at all times after the parts are assembled. The plug 49 is preferably shaped, as indicated, and carries below the clamp 41, a thrust ball bearing 51 and below this is mounted the spiral gear 39 to which reference has been had. This spiral turns freely on the plug 49 except that the periphery of the plug is recessed at 52 to provide places for the ratchet rollers 53 which are adapted to engage the interior of the gear 39, as shown in Figure 4, so as to form a ratchet connection which will permit a free movement of the gear 39 in one direction and cause the gear, plug and frietion cylinder to lock when moving in the direction indicated by the arrow in Figure 4. A cover plate 54, held by suitable screws 55, keepsthe rollers 53 in place and also the gear 39.

The upper ends of the spiral racks 38 are preferably provided with suitable pins 56 which prevent a separation of the parts. 7

From the foregoing it is apparent that when the distance between the crank 25 and pivot 27 is being shortened the racks 38 drive the gear 39 which in turn drives the cylinder 46 against the friction caused by the leather 45 under the influence of the clamps 41. There will be no substantial shortening of the distance between the pivots 25 and 27 until the clamp 5 rests on the paper 57 or other material which is being clamped, and then the distance between the pivots 25 and 27 is reduced against the opposition due to the turning of the cylinder 46 above described and this may be made as much or little as may be required, according to the tension put on the springs 43. After the crank pin or pivot 25 has reached the upper limit of its movement, it begins to descend and then the movement of the racks 38 is reversed with a corresponding reversal of the movement of the spiral gear 39 running idle on cylinder bearing 49 because the rollers 53 are designed to drive in one direction causing the pitman 26 to elongate without opposition. While it is elongating the clamp 5 is raised by mechanism which will be described below.

The spring clamp raising mechanism.

The clamp 5 is raised by the reverse movement of the shaft 14 and the mechanism for causing this reverse movement will now b described. The shaft 14 carries a segment gear 57 wh ch is fixed to this shaft so that it will not turn thereon by any suitable means, as a key 58 which is let into registering slots. This segment gear 57 engages a second segment gear 59 which is fixed on a shaft 60 that runs parallel withthe shaft 14 and has its end mounted so as to turn free in the frame. A key 61 holds the parts 59 and 60 in fixed relation durin rotating movement. The gear 59 is provi ed with a crank or pivot 62 which engages a link 63 in the conventional manner, and this link 63 runs to a pivot 64 of a toggle spring mechanism 65 which will now be described. The toggle spring mechanism 65 has at each end a ball 66 which rests in a corresponding socket 67 which is attached to the frame 3 in any suitable manner. Each ball 66 has a projecting rod 68 which enters a correspond ing tube 69 the other end of which has perforated ears 70 which engage the pivot 64. Coil springs 71 surround the telescoping parts 68 and 69 of each member and these compression springs extend from the balls 66 to shoulders 72 adjacent to the ears 70 so that they offer sufficient res stance of telescoping of the parts 68 and 69 to overbalance clamp 5 and subsidiary parts. These springs are under least tension and are longest when the clamp 5 is elevated to the limit set by the sto s 34 and 35 and each must compress when t e clamp 5 is on the table 2 even when there is no paper or other material held under the clamp. At such a time the parts 68 and 69 are nearly but not quite vertical and they never reach a dead center. If they did the springs 71 could not be effective to elevate th clamp and if they should, for any cause, go beyond the dead center they would act so as to tend to lower instead of raise the clamp. Therefore, it is essential that they function. as above set forth, and never reach the dead center. If desired, any suitable bearing may be substituted with a rod passing through the same and on which a spring is mounted. Th essence of this feature of my invention is in the toggle spring counter balance means. The exact connecting means may be varied.

M odz'fied clamping mechanism.

In the structure shown in Figures 6 to 8 inclusive, is found a different embodiment of the idea set forth in Figures 3, 4 and 5. In this embodiment the shaft 14 and arm 28 appear, as before, and the pivotal connection 27 is also employed to connect this arm with the sleeve 41. The interior of this sleeve 41 may be as shown in Figure 3 or it may be as shown in Figure 6, where the bore 1s conical and the leather lining 45 is made to correspond. This leather lining presses against a cone 72 which at its top has a bolt 73 surrounded by a washer 74 which presses on the divided sleev 41 and is held in fixed relation thereto by means of a nut 75. The lower end of this cone 7 2 is fixed to a spiral gear 76 by a key 77. or any other suitable means, so that the conical cyl lnder 72 and the gear 76 always have the same rotating movement. Ball bearings 7 6 separate this gear 76 from the sleeve 41. The divided or solid friction clamp 41 has guide bearings 40 which are made to receive the spiral pinions 78 which mesh with and drive the gear 76 or are driven by it fOT-liS normal position. The lower ends of the spirals are mounted so as to turn in the crank 0 hearing 37 which is connected to the crank 24, in the manner described above. Each spiral 78 has fixed thereon a ratchet 7 9 which engages a spring pressed pawl 80 or roller ratchets mounted in the usual manner, as shown in Figure 8. The lower ends of these spiral shafts 78 rest on suitable thrust ball bearings 81 which are held in place by means of suitable screw caps 82, or any other suitable means.

It will be understood that the parts of the sleeve 41, shown in Figure 6, are held in proper relation the same as the parts of the sleeve 41, shown in Figure 3.

It will be noted that the spirals 78 are opposite spirals and that the ratchets 79 are made to correspond. The purpose of this is that when the crossing 37 is elevated, as it is when the shaft 22 rotates, as above described, these spiral shafts will drive the spiral gear 76 and thereby turn the cone friction cylinder 72 against the friction imposed by theleather 45. On the return movement, this friction keeps the spiral gear 76 from turning and then 1t drives the spiral pinion 7 S and in consequence the pitman elongates, as above set forth. When the spiral pinions 78 drive, their respective ratchets and pawls keep them from revolving and when they are driven these pawls otter no interference to their rotation.

As the friction lining 45 wears the reguired friction is obtained through the nut Operation.

In view of the foregoing, the operation of to raise the clamp. It is understood that the clamping action of the clamp 5 is in opposition to these springs 71.

If it be desired to clamp by manual power, in addition to the foregoing, the foot treadle 17 may be depressed as above described, which will bring the clamp 5 down on the paper 57 before the automatic clamp will so function. In that event, the clamp functions both manually and with power, and if desired, the clamp may be held on the material which has been severed after the power means has functioned. Whenever the clamp is released, the springs 71 will immediately raise the same, as above set forth.

While I have shown and described one embodiment of my invention, it is obvious that it is not restricted thereto, but that it is broad enough to cover all structures that come within the scope of the annexed claims. It is also obvious that the foot pedal mechanism is not essential and may be dispensed wit-h, if desired.

Having thus described my invention, what I claim is:

1. In an apparatus of the class described, a clamp and means for elevatin the same, embodying in its construction, a s aft, means connecting the shaft to the clamp, a segment gear mounted on said shaft, a resilient flexible means engaging said segment gear, a foot treadle, means for mounting the same and means for connecting this treadle and the shaft so that the clamp may be operated by pressing on the treadle and against the resilient means.

2. In an apparatus of the class described, a clamp, a shaft adapted to be oscillated, means for causing said shaft to drive said clamp, a sleeve loosely mounted on said shaft, arms extending from said sleeve, clamping friction devices pivotally connected to said arms, a gear carried by said friction clamping devices and provided with a ratchet connection therewith, mechanism for driving said gear and means for driving said mechanism in two directions so as to cause a clamping action when driving in one direction and a release when driving in the other.

3. In an apparatus of the class described, a clamp, a shaft adapted to be oscillated and means for causing said shaft to drive said clamp, a sleeve loosely mounted on said shaft, arms extending from said sleeve, friction sleeves pivotally connected to said arms, a means adapted to turn in said friction sleeves, means for varying the pressure of the friction sleeves against the means, means for causing the friction means to turn against the friction sleeves engaging the same while said arms are swinging in one direction and means for causing one of said arms to drive the oscillating shaft while the friction means is rubbing against the friction sleeves engaging the same.

eeean 4:. In an apparatus of the class described, a clamp, a shaft adapted to oscillate and means for causing said shaft to drive said clamp, a sleeve loosely mounted on said shaft arms fixed to said sleeve, a projection adapted to rest on one of said arms, means for holding the projection in fixedrelation to said oscillated shaft so that this arm may drive said shaft through said projection in one direction only, and means for driving said sleeve so as to cause the clamp to function.

5. In an apparatus of the class described, a clamp and means for driving the same embodying in its construction a pitman which elongates and shortens, said pitman being composed of sleeves, the sleeves adapted to engage a friction means held between them, a spiral gear having a ratchet connection with said means so as to turn with the same in one direction only, a pair of gears engaging said spiral gear and means connecting said gears with a pivot, a washer at the top of said friction means,

' a bolt passing through said washer and into the ratchet on which the spiral gear operates.

65. In an apparatus of the class described, a clamp and means for driving the same embodying in its construction a pitman which elongates and shortens, said pitman being composed of sleeve members adapted to engage a friction means held between them, a spiral gear having a ratchet connection with said friction means so as to turn with the same in one direction only, a Hair of gears engaging said spiral gear an means connecting said gears with a pivot, a washer at the top of said friction means, a bolt passing through said washer and into the ratchet on which the spiral gear operates and a key holding the friction means and spiral supporting gear means in fixed relation.

7. In an apparatus of the class described, a clamp and means for actuating the same so that it will accommodate itself automatically to material of different thicknesses and means for elevating said clamp when free to rise embodying in its construction a link, a toggle pivotally connected to said link and springs on the two arms of said toggle which are set so as to raise said clamp or tend to raise the same.

8. In an apparatus of the class described, a clamp and means for actuating the same so that it will accommodate itself automatically to material of different thicknesses, and means for elevating said clamp when free to rise embodying in its construction a link, a toggle pivotally connected to said link and springs on the two arms of said. toggle which are set so as to raise said clamp or tend to raise the same.

9. In an apparatus at the class described,

a clamp and means for actuating the same so that it will accommodate itself automatically to material of different thicknesses, means for elevating said clamp when free to rise embodying in its construction a link, a toggle pivotally connected to said link and springs on the two arms of said toggle which are set so as to raise said clamp or tend to raise the same and ball and socket joints or other means at the ends of the arms of said toggle.

10. In an apparatus of the class described, a clamp and means for driving the same embodying in its construction a pitman which elongates and shortens, said itman being composed of a sleeve adapte to engage a friction device held in it, means for forcing the sleeve and friction device together, means for turning said friction device positively in one direction only, said friction device having a conical surface whereby wear may be taken up from time to time, as desired.

In testimony whereof, I have hereunto set my hand this 29th day of March, 1926.

JOHN F. SCHROETER. 

